Azufre literally means "sulfur," a chemical element often associated with brimstone and hell. It's a very unusual and dramatic word to find in a pop song, making it instantly memorable.
Shakira uses it to create a powerful metaphor, singing about a taste on the skin of "azufre revuelto con miel" (sulfur mixed with honey). This striking image perfectly captures the song's theme: a dangerous, toxic attraction that is also irresistibly sweet and tempting.
Colombian pop star Shakira knows she is making a terrible choice here, and that is exactly why the track works. The drama unfolds right in a hotel room: "En la suite, dieciséis / Lo que empieza no termina" ("In suite sixteen / What starts doesn't end"), complete with mini bar raids and noisy neighbor complaints from room seventeen. She describes her lover as tasting like "azufre revuelto con miel" ("sulfur mixed with honey"), a blunt way to say someone is equal parts sweet and toxic. She even catches him slipping a ring into his pocket, yet admits, "No hay ceguera peor / Que no querer mirar" ("There is no worse blindness than not wanting to look"). She ignores the red flag anyway and goes for a walk on the wild side.
The chorus hits with pure self-awareness: "Lo hecho está hecho / Volví a tropezar / Con la misma piedra que hubo siempre" ("What's done is done / I tripped again over the exact same stone"). In Spanish, tripping over the same stone (tropezar con la misma piedra) is a classic idiom for repeating your exact mistakes. Shakira calls herself an expert at picking the wrong guys, laughing off the guilt with "Se siente tan bien todo lo que hace mal" ("Everything that hurts feels so good"). Instead of falling into regret, she shrugs it off with a reminder that everything in life is temporary, including this bad romance.